EP 0 959 978 B1 discloses a filter which includes a housing which, in turn, is comprised of two screwed-together housing parts. For producing a reliable detent connection between filter element and a cover housing part, a recess is provided in the area of the cover housing part. This recess has different functional areas, namely a locking area, a retaining area, a translation area and an insertion/removal area which are necessary for effecting or for releasing the detent connection. Detent means of the filter element can be moved between the functional areas by relative rotations between the filter element and the cover housing part.
There remains a need in the art for a filter element, a fastening housing part, and a releasable detent connection configured in such a way that the filter element can be inserted into and removed from the filter housing in an easier and more reliable way and further, when exchanging the filter element, no fluid from the filter should reach uncontrollably the surroundings, if possible.